The Jackson Laboratory was founded in 1929 by Dr. Clarence Cook Little as a mammalian genetics center with a special focus on the problem of cancer, on the role of genes in both normal and abnormal development and differentiation, and on the development of the requisite genetic tools which could be put to practical use by others in examining these questions. It is the premise of The Jackson Laboratory that basic research directed towards a better understanding of the fundamental mechanisms that control normal and neoplastic growth, differentiation, and development, is essential to understand how cancers originate, develop and metastasize. The investigations pursued by members of the Scientific Staff are interdisciplinary in nature, as is illustrated by the number and diversity of internal and external collaborative projects carried out at the Laboratory. In addition to specific cancer-related research, the basic research carried out by The Jackson Laboratory investigators lays the essential ground work for a better understanding of neoplasia. Organizational capabilities and physical facilities of the Laboratory foster cohesiveness of research effort, and the deliberate avoidance of departmentalization actively promotes interdisciplinary cooperation among Scientific Staff Members. An additional factor contributing to productive research interactions is the widespread use of shared scientific resources and services, especially the genetic resources, as well as shared equipment. The Center Director is also the Director of the Laboratory and reports to the Board of Governing Trustees. The Director controls the total budget, allocates all space and makes all appointments to the Scientific Staff, subject to confirmation by the Board of Governing Trustees. The Jackson Laboratory as a whole has been designated by NCI as a Laboratory Cancer Research Center and with this application seeks continuation of it Cancer Center Support (CORE) Grant. The request is for continuing support for the current components of the grant and for additional support for two new components. CORE support is requested for only 20.6% of the total cost of the Resources and Services involved.